LIGHTING HIGH BAY AREAS WITH ELECTRODELESS LAMPS

At the National Air and Space Museum (NASM), Smithsonian institution, in Washington, DC, the existing high intensity discharge luminaires in three high bay areas have reached tile end of their effective useful life. The standard mercury lamp and the magnetic ballast in an open fr ont fixture presented serious maintenance as well as disposal problems . Retrofitting of existing equipment had been accomplished to correct the most serious problems, but the museum desired a long-term solution involving innovative approaches to the illumination of tile space, Th e design solution involved the Department of Energy; Fusion Lighting S ystem of Rockville, MD, Lorne Whitehead of Vancouver, BC; and NASM. Th e result was a prototype sulfur lighting system (SLS), which includes an electrodeless light source driven by microwave energy and a 250 mm diameter by 23 m long light pipe. Three light sources and three light pipes have been installed on a north-south asis, mounted near the exis ting luminaires. The SLS provides ease of access for maintenance, a co llimated light pattern, and a long life, energy efficient source. The SLS employs total internal reflection (TIR) principles for the distrib ution of light. The TIR principle decreases apparent glare while colli mating die light into the high bay area. The SLS has a color rendering index greater than 80, far exceeding the exisiting systems' CRI of 50 or less. The prototype, as well as the old system, has been installed and is operational. Both systems have been measured by Lawrence Berke ley Laboratory. Both systems' data have been compiled into charts show ing the energy savings and changes in light levels.